Isuzu KB P190. Manual - part 422

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-71

DTC P0045 (Flash Code 33)

Circuit Description

The position of the turbocharger nozzle is controlled by
the ECM. The ECM utilizes a turbocharger nozzle
control solenoid valve and a boost pressure sensor to
control the turbocharger nozzles. When the engine is
not under load, the turbocharger nozzles are in an open
position, or no boost condition. When the engine is
under load, the ECM commands the control solenoid
valve to close the turbocharger nozzles, thus
increasing the boost. The ECM will vary the boost
dependant upon the load requirements of the engine.
The ECM uses a pulse width modulation (PWM) on the
control circuit to open and control the solenoid valve. If
the ECM detects an open circuit or short circuit on the
solenoid valve circuit, this DTC will set.

Condition for Running the DTC

• The ignition switch is ON.

Condition for Setting the DTC

Either of following condition is met:

• The ECM detects a low voltage condition on the

turbocharger nozzle control solenoid circuit when
the solenoid is commanded OFF.

• The ECM detects a high voltage condition on the

turbocharger nozzle control solenoid circuit when
the solenoid is commanded ON.

Action Taken When the DTC Sets

• The ECM illuminates the MIL when the diagnostic

runs and fails. Refer to DTC Type Definitions for
Action Taken When the DTC Sets - Type A.

• The ECM limits fuel injection quantity.

• The ECM inhibits pilot injection.

• The ECM inhibits cruise control.

Condition for Clearing the DTC

• Refer to DTC Type Definitions for Condition for

Clearing the MIL/ DTC - Type A.

Diagnostic Aids

• If an intermittent condition is suspected, refer to

Intermittent Conditions in this section.

Test description

The number below refers to the step number on the
Circuit/ System Testing.
4. If the solenoid control circuit between the ECM and
the solenoid is normal, the test lamp changes from
Bright to Dim when commanded from Increase to
Decrease.

Schematic Reference: Vacuum Hose Routing
Diagram and Engine Controls Schematics

Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views

Circuit/ System Testing DTC P0045

Step

Action

Value(s)

Yes

Did you perform the Diagnostic System Check -
Engine Controls?

—

Go to Step 2

Go to Diagnostic

System Check -
Engine Controls

Install a scan tool.

Turn OFF the ignition for 30 seconds.

Start the engine.

Monitor the DTC Information with a scan tool.

Does the DTC fail this ignition?

—

Go to Step 3

Go to Diagnostic

Aids

Turn OFF the ignition.

Disconnect the turbocharger nozzle control
solenoid valve harness connector.

Connect a test lamp between the ignition
voltage feed circuit (pin 2 of E-106) and a
known good ground.

Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

—

Go to Step 4

Go to Step 5

6E-72 ENGINE CONTROL SYSTEM (4JK1/4JJ1)

Connect a test lamp between the control
circuit (pin 1 of E-106) and battery voltage.

Perform the Turbocharger Solenoid Control
with a scan tool.

Command the solenoid valve Increase and
Decrease while observing the test lamp.

Does the test lamp change brightness when
commanded Increase and Decrease?

—

Go to Step 7

Go to Step 6

Repair the open circuit or high resistance between
the Engine (10A) fuse and the solenoid valve (pin 2
of E-106). Check the Engine (10A) fuse first.

Did you complete the repair?

—

Go to Step 11

—

Test the control circuit between the ECM (pin
66 of E-90) and the solenoid valve (pin 1 of E-
106) for the following conditions:

• An open circuit

• A short to ground

• A short to battery or ignition voltage

• High resistance

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 11

Go to Step 8

Inspect for an intermittent and for poor
connections at the harness connector of the
solenoid valve (pins 1 and 2 of E-106).

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 11

Go to Step 9

Turn OFF the ignition.

Disconnect the ECM harness connector.

Inspect for an intermittent and for a poor
connection at the harness connector of the
ECM (pin 66 of E-90).

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 11

Go to Step 10

Replace the turbocharger nozzle control solenoid
valve.

Did you complete the replacement?

—

Go to Step 11

—

Important: Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.

Did you complete the replacement?

—

Go to Step 11

—

Reconnect all previously disconnected fuse or
harness connector(s).

Clear the DTCs with a scan tool.

Turn OFF the ignition for 30 seconds.

Start the engine.

Operate the vehicle within the Conditions for
Running the DTC. You may also operate the
vehicle within the conditions that you
observed from the Freeze Frame/ Failure
Records.

Did the DTC fail this ignition?

—

Go to Step 3

Go to Step 12

Step

Action

Value(s)

Yes

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-73

Observe the DTC Information with a scan tool.

Are there any DTCs that you have not diagnosed?

—

Go to DTC List

System OK

Step

Action

Value(s)

Yes

6E-74 ENGINE CONTROL SYSTEM (4JK1/4JJ1)

DTC P0087 (Flash Code 225)

Description

The common rail fuel system is comprised of two fuel
pressure sections: a suction side between the fuel tank
and the fuel supply pump and a high-pressure side
between the fuel supply pump and the fuel injectors.
Fuel is drawn from the fuel tank via a feed pump and
then pumped into the fuel rail by two plungers, all of
which are internal to the fuel supply pump. This high
pressure is regulated by the ECM using the fuel rail
pressure (FRP) regulator dependant upon values from
the FRP sensor attached to the fuel rail. In case of fuel
rail overpressure, a pressure limiter valve threaded into
the fuel rail will open to release overpressure and
return fuel back to the fuel tank. If the ECM detects that
the fuel rail pressure went excessively high, then
sharply decreased, this DTC will set indicating high fuel
pressure, which activated the pressure limiter valve.

Condition for Running the DTC

• DTCs P0192 and P0193 are not set.

• The battery voltage is more than 9 volts.

• The ignition switch is ON.

• The engine is running.

Condition for Setting the DTC

• The ECM detects that the pressure limiter valve is

activated with overpressure (more than 190 MPa
[27,600 psi]) in the fuel rail.

Action Taken When the DTC Sets

• The ECM illuminates the MIL when the diagnostic

runs and fails. Refer to DTC Type Definitions for
Action Taken When the DTC Sets - Type A.

• The ECM limits fuel injection quantity.

• The ECM inhibits pilot injection.

• The ECM inhibits cruise control.

Condition for Clearing the DTC

• Refer to DTC Type Definitions for Condition for

Clearing the MIL/ DTC - Type A.

Diagnostic Aids

• An intermittently sticking FRP regulator may have

allowed the fuel pressure to become high enough
to open the pressure limiter valve.

• A skewed FRP sensor value can set this DTC. The

FRP Sensor on the scan tool should read 0.9 to
1.0 volt with the key ON and engine OFF after the
engine has stopped running for a minimum of 1
minute.

Notice:

• If the fuel tank is empty or near empty, air might be

allowed to go into the fuel system. With air in the
fuel system, smooth flow of fuel into the supply
pump is interrupted and this DTC may set. Perform
bleeding of fuel system after refilling.

Schematic Reference: Fuel System Routing Diagram
and Engine Controls Schematics

Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views

Circuit/ System Testing DTC P0087

Step

Action

Value(s)

Yes

Did you perform the Diagnostic System Check -
Engine Controls?

—

Go to Step 2

Go to Diagnostic

System Check -
Engine Controls

Install a scan tool.

Turn OFF the ignition for 30 seconds.

Start the engine.

Monitor the DTC Information with a scan tool.

Is DTC P0088, P0089, P0091, P0092, P0192,
P0193, P0201 - P0204, P1064, P1065, P124B or
P2146 - P2151 set?

—

Go to Applicable

DTC

Go to Step 3

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